I thought this was quite interesting, given that both of these games are arguably their respective consoles biggest exclusive game...
Anyway, Halo 4 has sold 7,030,950 in its first 7 weeks on sale. It took GT:5 58 weeks to sell as much as this. Pretty amazing!
My prediction threads:
Wii U will sell under 40m units (made on 14th September 2012)
PS Vita will sell under 20m units (made on 30th September 2012)
Wii U will sell under 7m in 2013 - I was right